Do phytotoxic allelochemicals remain in ashes after burning Chrysanthemoides monilifera subsp. monilifera (boneseed)?

Australia is facing challenges in controlling Chrysanthemoides monilifera subsp. monilifera(boneseed). However, burning has achieved some success in this regard. We aimed to investigate the comparative phytotoxicity of boneseed dried powder and ashes(burnt at 450℃ and250℃). Phenolic compounds in powder and ashes were measured using Folin–Ciocalteu assay and HPLC. The phytotoxicity of boneseed powder and ash extracts was assessed through germination bioassay on Lactuca sativa and the phytotoxicity of litter and ashes was evaluated using field soil, both in growth chamber. Burning of boneseed reduced total phenolics in ashes of boneseed organs by 99% and 100% both at high and low temperatures. The four phenolic compounds that were detected in boneseed were either absent or at negligible levels in the ashes,with inversely related to temperature. Both boneseed ash extracts and litter ash-mediated soil significantly reduced phytotoxicity displaying increased germination, biometric and biochemical parameters of test species compared with unburnt powder extracts and litter powder-mediated soil respectively, with greater reduction of phytotoxicity found for ashes produced at the lower temperature. Interestingly, the ash extracts and litter ash-mediated soil were found to stimulate some of those parameters of the test species compared to control. There was no excessive reactive oxygen species(ROS) produced in test species exposed to ash extracts compared with unburnt powder extracts. These findings suggest that burning of boneseed is an appropriate method of weed control and that this approach will reduce phytotoxicity of this species on native plants.     

The Impact of Projected Climate Change Scenarios on Nitrogen Yield at a Regional Scale for the Contiguous United States

Improved understanding of the potential regional impacts of projected climatic changes on nitrogen yield is needed to inform water resources management throughout the United States (U.S.). The objective of this research is to look broadly at watersheds in the contiguous U.S. to assess the potential regional impact of changes in precipitation (P) and air temperature (T) on nitrogen yield. The SPAtially Referenced Regression On Watershed attributes model and downscaled P and T outputs from 14 general circulation models were used to explore impacts on nitrogen yield. Results of the analysis suggest that projected changes in P and T will decrease nitrogen yield for the majority of the contiguous U.S., including the watersheds of the Chesapeake Bay and Gulf of Mexico. Some regions, however, such as the Pacific Northwest and Northern California, are projected to face climatic conditions that, according to the model results, may increase nitrogen yield. Combining the projections of climate‐driven changes in nitrogen yield with projected changes in watershed nitrogen inputs could help water resource managers develop regionally specific, long‐term strategies to mitigate nitrogen pollution.     

Application of enrichment factor,geoaccumulation index,and ecological risk index in assessing the elemental pollution status of surface sediments

Environmental Geochemistry and Health - Sediment can accumulate trace elements in the environment. This study profiled the magnitude of As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, and Zn pollution in...     

Evaluation of fungal potentiality for bioconversion of domestic wastewater sludge

This study was undertaken to screen the filamentous fungi isolated from its relevant habitats (wastewater, sewage sludge and sludge cake) for the bioconversion of domestic wastewater sludge. A total of 35 fungal strains were tested against wastewater sludge (total suspended solids, TSS 1%-5% w/w) to evaluate its potentiality for enhancing the biodegradability and dewaterability using liquid state bioconversion(LSB) process. The strains were divided into five groups i. e. Penicillium, Aspergillus, Trichoderma, Basidiomycete and Miscellaneous, respectively. The strains WWZP1003, SCahmA103, SCahmT105 and PC-9 among their respective groups of Penicillium,Aspergillus, Trichoderma and Basidiomycete played potential roles in terms of separation (formation of pellets/flocs/filaments),biodegradation(removal of COD) and filtration(filterability) of treated domestic wastewater sludge. The Miscellaneous group was not considered due to its unsatisfactory results as compared to the other groups. The pH value was also influenced by the microbial treatment during fermentation process. The filterability of treated sludge was improved by fungal treatment, and lowest filtration time was recorded for the strain WWZP1003 and SCahmA103 of Penicillium and Aspergillus groups respectively compared with other strains.     

Space-time Bayesian small area disease risk models: development and evaluation with a focus on cluster detection

This paper extends the spatial local-likelihood model and the spatial mixture model to the space-time (ST) domain. For comparison, a standard random effect space-time (SREST) model is examined to allow evaluation of each model’s ability in relation to cluster detection. To pursue this evaluation, we use the ST counterparts of spatial cluster detection diagnostics. The proposed criteria are based on posterior estimates (e.g., misclassification rate) and some are based on post-hoc analysis of posterior samples (e.g., exceedance probability). In addition, we examine more conventional model fit criteria including mean square error (MSE). We illustrate the methodology with a real ST dataset, Georgia throat cancer mortality data for the years 1994–2005, and a simulated dataset where different levels and shapes of clusters are embedded. Overall, it is found that conventional SREST models fair well in ST cluster detection and in goodness-of-fit, while for extreme risk detection the local likelihood ST model does best.     

Elucidation of ecosystem attributes of an oligotrophic lake in Hokkaido,Japan, using Ecopath with Ecosim (EwE)

The fishing practices in the oligotrophic Lake Toya, Hokkaido, Japan, have profound implications in the ecosystem sustainability. The status of the sockeye salmon (Oncorhynchus nerka) population has become a serious concern among the lake managers and policy makers during the last decades. While the decline of the sockeye salmon population has been well documented in Lake Toya, there is considerable uncertainty with regards to the impact on the broader system dynamics. In this study, our objective is to address this knowledge gap by undertaking a synthesis of the Lake Toya food web using the mass-balance modeling software Ecopath with Ecosim (EwE). Our primary research question is to examine the repercussions of the declining sockeye salmon population on the trophic dynamics of the lake. Namely, we assess if there are any competing species that might have benefited from the decrease of sockeye salmon standing biomass and to what extent do these changes propagate through the Lake Toya food web? Our analysis pinpoints the critical role of the Japanese smelt (Hypomesus transpacificus nipponensis) in the system, which demonstrates a wide range of effects on several functional groups at both higher and lower trophic levels in Lake Toya. In particular, being a substantial portion of the masu salmon (Oncorhynchus masou) and adult sockeye salmon diets, the Japanese smelt has a positive impact on the top predators of the system. Amphipods, insects, and shrimp strongly benefit from the autochthonous and allochthonous organic matter in the system, while the tight coupling between phytoplankton and zooplankton seems to be particularly critical for the integrity of the Lake Toya food web. Whereas the values of the different ecosystem attributes (e.g., primary production/biomass, biomass/total throughput, system omnivory index, amount of recycled throughput, Finn's cycling index) provide evidence that Lake Toya is an immature system, we note that the internal redundancy and the system overhead estimates suggest that the lake possesses substantial reserves to overcome external perturbations. We also examined the effects of a variety of fishing policies on the biomass of masu salmon and adult sockeye salmon, which verify the belief that the adult sockeye population is quite fragile with high likelihood to collapse. Our analysis also predicts that sockeye will not rebound unless the fishing pressure exerted is substantially reduced (>50% of the reference levels used). Masu salmon seems to benefit under all the scenarios examined indicating that the intensity of the current fishing activities is significantly lower than its biomass accumulation rate in the system.     

An Overview on Starch-Based Sustainable Hydrogels: Potential Applications and Aspects

Hydrogels are a kind of three dimensional polymeric network system which has a significant amount of water imbibing capacity despite being soluble in it. Because of the potential applications of hydrogels in different fields such as biomedical, pharmaceutical, personal care products, biosensors, and cosmetics, it has become a very popular area of research in recent decades. Hydrogels, prepared from synthetic polymers and petrochemicals are not ecofriendly. For preparing biodegradable hydrogels, most available plant polysaccharides like starch are utilized. In its structure, starch has a large number of hydroxyl groups that aid in hydrogel networking. For their easy availability and applications, starch-based hydrogels (SHs) have gained huge attention. Moreover, SHs are non-toxic, biocompatible, and cheap. For these reasons, SHs can be an alternative to synthetic hydrogels. The main focus of this review is to provide a comprehensive summary of the structure and characteristics of starch, preparation, and characterization of SHs. This review also addresses several potential multidimensional applications of SHs and shows some future aspects in accordance.

Graphic abstract